The present invention relates to a digital audio data input system for an optical disk reproducing apparatus, more particularly, to a system for controlling continuous data input for an optical disk in which a data input controller is provided to input continuously, when the speed of transmission to a host computer returns to a normal state after an input operation of digital audio data is interrupted on account of an overflow in a buffer ROM, the data from the data input stop point.
In conventional optical disk reproducing system, when a digital audio data on an optical disk read by a disk pickup is transmitted to a host computer through an optical disk digital signal processing unit and an optical disk ROM decoding unit, the optical disk ROM decoding unit stores a serial data stream inputted from the optical disk digital signal processing unit to a buffer RAM, for decoding the data and transmitting the data to the host computer, and then once a predetermined amount of data is stored in the buffer RAM, it begins to transmit the data to the host computer. At this time, in case that the speed of transmission of data to the host computer is same as or faster than the speed that the optical disk digital signal processing unit reads the data, there arises no problem. But, in case that the transmission speed is slower (this phenomenon in due to the processing speed of the host computer and takes place in case that the host computer attends to tasks other than the data reception.), the data not transmitted to the buffer RAM is piled up, resulting in an overflow phenomenon. At this moment, the optical disk ROM decoder stops the data input operation from the optical disk digital signal processing unit and has to notice this point so that when the buffer RAM is available, the data from the interruption point can be inputted from the optical disk digital signal processing unit.
In such a conventional optical disk reproducing system, the data read out of the disk is processed at the optical disk digital signal processing unit into a desired data and outputted to the optical disk ROM decoding unit in the serial format. At this time, the optical disk ROM decoding unit detects 12 bytes of synchronizing pattern FF, OO, FF, FF, FF, FF, FF, FF, FF, FF, OO, FF out of serial data and then starts to receive the serial data. The data format recorded in the ROM disk of the optical disk player has 12 bytes of synchronizing pattern so that the optical disk ROM decoding unit can receive the data. However, because there are no such 12 bytes synchronizing pattern in the digital signal data format recorded in the disk of the optical disk player, the data can not be inputted to the optical disk ROM decoding unit in an appropriate timing. Also, when the input operation is interrupted by an overflow of buffer, it is not possible to meet the input retry timing precisely.